Task: validate CUSTOMERS file before use

[alexellis]

Expected Behaviour

We should validate all entries in the CUSTOMERS file before use - to prevent anyone getting their functions overriden by accident. See issue #314

Possible Solution

Since this is relying on a human element of not merging a PR to the customers file with two potentially clashing usernames, we should implement a unit test and sdk method in the sdk of OpenFaaS Cloud that can validate a list of usernames.

I.e.

OK

alexellis
stefan
ivana

Not OK

alexellis
alexellis-suffix
stefan
ivana

Not OK

alexellis
stefan
stefan-prodan
ivana

OK

alexellis
stefan-prodan
ivana

[alexellis]

The PR should be raised here: https://github.com/openfaas/openfaas-cloud/tree/master/sdk

[alexellis]

No need to test end-to-end, just via unit tests.

https://blog.alexellis.io/golang-writing-unit-tests/

[rajatjindal]

how about

alexellis   
stefan-prodan  
stefan  
ivana

and

alexellis
alexe
stefan
ivana

[alexellis]

What about it?

[alexellis]

alexe won't clash because of the separator being -

[alexellis]

alexe => alexe-my-function
alexellis => alexellis-my-function